The present invention relates to an exposure apparatus which includes an interferometer system which measures the position and displacement of an object in the vertical direction and is used to manufacture a liquid crystal board or semiconductor device.
FIGS. 13 and 14 show an example of a measuring means for an alignment apparatus used in a conventional semiconductor exposure apparatus or the like. FIG. 13 is a perspective view showing the arrangement of a measuring system using a laser interferometer. FIG. 14 is a front view showing the overall conventional semiconductor exposure apparatus having the measuring system.
In FIG. 14, reference numeral 7 denotes an illumination unit for illuminating a reticle pattern; 8, a reticle having a pattern to be transferred; 9, a projection lens for projecting a reticle pattern onto a wafer; 10, a lens barrel support which supports the projection lens 9; 11, a stage surface plate; 13, an X stage; 14, a Y stage; 15, an X stage driving guide/X linear motor; and 16, a Y stage driving guide/Y linear motor. A top stage 2 for precise alignment is mounted on the X and Y stages. The top stage 2 moves a long stroke in the X- and Y-axis directions by the guides 15 and 16 and an actuator. Further, the top stage 2 moves a short stroke in the Z-axis direction and rotational directions xcfx89X, xcfx89Y, and xcex8 by a Z actuator 17 which drives the top stage 2 with respect to the X stage 13.
In FIG. 13, reference numeral 1 denotes a wafer chuck which supports a wafer (not shown). The top stage 2 constitutes a stage which supports the wafer chuck 1. Reference numeral 3 denotes an X mirror which is attached to the top stage 2 and has a reflecting surface perpendicular to the X-axis; 4, a Y mirror which is attached to the top stage 2 and has a reflecting surface perpendicular to the Y-axis; 5a, 5b, and 5c, X interferometers for measuring an X position; and 6a and 6b, Y interferometers for measuring a Y position. The X interferometers 5a, 5b, and 5c, and Y interferometers 6a and 6b are fixedly supported by a lens barrel support 10 shown in FIG. 14.
In alignment by an apparatus conventionally called an alignment apparatus, a laser beam is sent to strike each predetermined position on a reflecting mirror attached to a stage. Position variation information at the beam incident position along the beam incident direction is acquired from the reflected beam to perform position detection. Alignment control is done based on the detection result. As a rotational direction detection means, pieces of position variation information at two beam incident positions along a single axis are obtained. More specifically, the measuring system in FIG. 13 detects positions in the X, xcex8, and xcfx89Y directions from pieces of position variation information based on the X interferometers 5a, 5b, and 5c and in the Y and xcfx89X directions by the Y interferometers 6a and 6b. Alignment control along the five axes except for the Z-axis is performed based on pieces of position detection information by the laser interferometers.
Referring back to FIG. 14, reference numerals 12 denote Z displacement sensors such as linear encoders or electrostatic capacitance sensors arranged in the above-described stage. The Z displacement sensors 12 measure displacement of the top stage 2 with respect to the X stage 13 at three positions, and can measure displacements of the top stage 2 in the Z and tilt directions. The Z tilt direction of the top stage 2 with respect to the lens barrel support 10 can be measured from the measurement values of the Z displacement sensors 12 and those of three interferometers (not shown) for performing Z measurement of the stage surface plate 11 with respect to the lens barrel support 10. Z-axis alignment control is executed based on the detection results.
Alternatively, Z measurement of the top stage 2 may be directly performed using an interferometer, as shown in FIG. 15. In FIG. 15, reference numeral 18 denotes a mirror attached to the lens barrel support 10 in order to perform Z measurement; 19, a mirror which is integrally made up of an X mirror and a Z measuring mirror which forms an acute angle with the X mirror, and reflects, to the Z direction, measurement light incident parallel to the plane in which the top stage 2 moves; and 20, a Z measuring interferometer 20. This measuring method can directly measure the Z position and displacement of the top stage 2 by using the lens barrel support 10 as a measurement reference.
The alignment apparatus using the above Z position detection means suffers from the following problems.
In the prior art shown in FIGS. 13 and 14, Z position information of the top stage is obtained from the positional relationship between the X stage and the top stage. A measurement error occurs due to deformation of the stage guide when the stage accelerating/decelerating inertial force or stage weight acts as a moving load, or by deformation of the surface stage or structure which supports the stage. This inhibits precise alignment.
In the prior art shown in FIG. 15, the X or Y measuring mirror and the Z measuring mirror having an inclined surface are integrated. The X or Y measuring mirror which must exhibit high precision undergoes processing or mirror adhesion for Z measurement. This decreases the flatness and alignment precision. The alignment precision also decreases owing to an increase in weight or deformation caused by changes in adhesive over time.
The present invention has been proposed to solve the conventional problems, and has as its object to provide an exposure apparatus including an interferometer system that enable Z-direction measurement using a lens barrel support as a measurement reference and enable high-precision alignment by only mounting a bar mirror on a stage.
To solve the above problems, an exposure apparatus according to the present invention, having a projection optical system for projecting a pattern formed on a master onto a substrate, a stage capable of moving with respect to the projection optical system while holding at least one of the substrate and master, and a lens barrel support which supports the projection optical system, includes: an interferometer system having an interferometer for measuring a Z position and displacement of the stage with respect to the lens barrel support by using a Z measuring mirror which is arranged on the stage and has a reflecting surface substantially parallel to an XY plane.
More specifically, the exposure apparatus comprises a projection optical system for projecting a pattern formed on a master onto a substrate, a stage capable of moving with respect to the projection optical system while holding the substrate or master, and a lens barrel support which supports the projection optical system, and includes an interferometer system having an interferometer for measuring the position or displacement of the stage with respect to the lens barrel support. In this arrangement, the interferometer is arranged on at least one of the X and Y movable portions of the stage. Measurement light emitted by the interferometer is guided almost perpendicularly to the XY plane. The measurement light is reflected by a first reflecting surface attached to the lens barrel support toward the center of the lens barrel support, and travels toward a second reflecting surface at the center.
The measurement light is reflected by the second reflecting surface to almost perpendicularly strike a bar mirror having a reflecting surface almost parallel to the moving plane of the stage. Z measurement is performed by the reflected measurement light.
In the exposure apparatus, the interferometer system desirably includes a plurality of interferometer systems arranged on the apparatus. The interferometer may be mounted on either of the stage and a movable portion which follows the stage. The stage may have an elongated mirror for Z measurement which is longer in the stroke direction of the movable portion which supports the interferometer, and the elongated mirror for Z measurement may use the upper surface of either of the X and Y measuring mirrors. In the interferometer system, measurement light emitted by the interferometer may strike the Z measuring mirror via a plurality of mirrors or prisms attached to the lens barrel support serving as a measurement reference. Measurement light incident on the Z measuring mirror is preferably almost perpendicular to the reflecting surface.
The interferometer desirably emits a total of four beams including two measurement beams and two, reference beams, and the four beams are desirably formed with a cross-shaped positional relationship at an almost equal interval. A mirror or prism arranged immediately in front of the Z measuring mirror desirably has at least two reflecting surfaces for reflecting measurement light to the Z measuring mirror and reference light back to the incident optical path.
An exposure apparatus according to the present invention comprises a Y stage movable in a Y direction; an X stage movable in an X direction with respect to the Y stage; a Z mirror which is mounted on the X stage or Y stage and has a reflecting surface parallel to an XY plane, a mirror or prism for guiding to the Z mirror a beam emitted in a Z direction by the Y stage; and an interferometer for detecting a Z position of the X stage or Y stage by using the beam reflected by the Z mirror.
In this case, the interferometer is desirably mounted on the Y stage or X stage. The interferometer is desirably mounted in the X or Y direction, the exposure apparatus desirably further comprises an optical element having a reflecting surface for reflecting a beam from the X or Y direction to the Z direction, and the interferometer desirably emits a beam parallel to the X or Y direction toward the optical element. The mirror or prism for guiding the beam to the Z mirror may have a first mirror or prism for reflecting to the X or Y direction a beam emitted to the Z direction by the Y stage or X stage, and a second mirror or prism for reflecting to the Z direction the beam reflected by the first mirror or prism and irradiating the Z mirror with the beam. The first mirror or prism and the second mirror or prism are desirably elongated in the X or Y direction. The second mirror or prism preferably has a reflecting surface for reflecting to the first mirror or prism a reference light component of the beam reflected by the first mirror or prism.
A semiconductor device manufacturing method according to the present invention comprises the steps of installing a plurality of semiconductor manufacturing apparatuses including any one of the above-described exposure apparatuses, in a semiconductor manufacturing factory, and manufacturing a semiconductor device by using the plurality of semiconductor manufacturing apparatuses.
Preferably, the semiconductor device manufacturing method further comprises the steps of connecting the plurality of semiconductor manufacturing apparatuses to a local area network; connecting the local area network to an external network outside the semiconductor manufacturing factory; acquiring information about the exposure apparatus from a database on the external network by using the local area network and the external network; and controlling the exposure apparatus on the basis of the acquired information.
Preferably, in the semiconductor device manufacturing method, a database provided by a vendor or user of the exposure apparatus is accessed via the external network, thereby obtaining maintenance information of the manufacturing apparatus by data communication, or data communication is performed between the semiconductor manufacturing factory and another semiconductor manufacturing factory via the external network, thereby performing production management.
A semiconductor manufacturing factory according to the present invention comprises a plurality of semiconductor manufacturing apparatuses including any one of the above-described exposure apparatuses, a local area network for connecting the plurality of semiconductor manufacturing apparatuses, and a gateway for connecting the local area network to an external network outside the semiconductor manufacturing factory, wherein information about at least one of the plurality of semiconductor manufacturing apparatuses can be communicated.
A maintenance method for an exposure apparatus installed in a semiconductor manufacturing factory according to the present invention comprises the steps of preparing a database for accumulating information about maintenance of the exposure apparatus on an external network outside a factory where any one of the above-described exposure apparatuses is installed, connecting the exposure apparatus to a local area network in the factory, and maintaining the exposure apparatus on the basis of information accumulated in the database by using the external network and the local area network.
Preferably, the exposure apparatus according to the present invention further comprises an interface for connecting a network; a computer for executing network software for communicating maintenance information of the exposure apparatus via the network; and a display for displaying the maintenance information of the exposure apparatus that is communicated by the network software executed by the computer.
Preferably, in the exposure apparatus according to the present invention, the network software provides on the display a user interface for accessing a maintenance database which is provided by a vendor or user of the exposure apparatus and connected to the external network outside a factory where the exposure apparatus is installed, and enables obtaining information from the database via the external network.
Other features and advantages of the present invention will be apparent from the following description taken in conjunction with the accompanying drawings, in which like reference characters designate the same or similar parts throughout the figures thereof.